The Double Diamond Model
The Double Diamond is a visual framework created by the UK Design Council in 2005 that maps the design process into four distinct phases: Discover, Define, Develop, and Deliver. It's called the 'Double Diamond' because the process involves two phases of divergent thinking (exploring widely) followed by convergent thinking (narrowing down) — creating a diamond shape twice. This model is used at organizations from the BBC to the UK Government Digital Service and provides a shared language for designers, product managers, and stakeholders to understand where they are in the design process and what kind of thinking is appropriate at each stage.
Diamond 1: Designing the Right Thing
- Discover (Diverge): Open up the problem space. Research broadly — talk to users, analyze competitors, review analytics, explore adjacent industries. The goal is to learn as much as possible without filtering. Deliverables: research reports, interview transcripts, analytics summaries, empathy maps
- Define (Converge): Narrow down the findings into a clear, specific problem statement. Synthesize research through affinity mapping, identify patterns and themes, and define the core problem to solve. Deliverables: user personas, problem statements, 'How Might We' questions, prioritized opportunity areas
- Key insight: Most teams skip Diamond 1 entirely — they start with a solution ('build a chatbot') rather than a problem ('users can't find answers to common questions'). Diamond 1 ensures you're solving the right problem before you design anything
Diamond 2: Designing Things Right
- Develop (Diverge): Generate multiple solutions to the defined problem. Sketch, wireframe, prototype, and explore different approaches. The goal is quantity and variety — avoid committing to one solution too early. Deliverables: sketches, wireframes, multiple prototype variations, concept boards
- Deliver (Converge): Refine the best solution through testing and iteration. Create high-fidelity designs, conduct usability tests, iterate based on feedback, and prepare for development handoff. Deliverables: final UI designs, prototypes, design specifications, test reports
- Real-world example: When the UK Government redesigned GOV.UK, Diamond 1 revealed that citizens couldn't find information across 750+ government websites. The defined problem: 'Citizens need one place to find government services.' Diamond 2 explored many solutions — a search engine, a directory, a unified site — and ultimately delivered a single, clean website that replaced all 750 sites, saving citizens an estimated 2 billion pounds annually
Practical Application of the Double Diamond
The most powerful aspect of the Double Diamond is its ability to align teams. When a stakeholder asks 'why aren't we designing yet?' you can point to the framework: 'We're in the Discover phase of Diamond 1 — we're making sure we understand the problem before we invest in solutions.' Similarly, when engineers ask 'is this design final?' you can say 'We're in the Develop phase of Diamond 2 — we're still exploring options and will converge after testing.' The common mistake is treating the Double Diamond as strictly linear. In reality, you may loop back: testing in Deliver might reveal you defined the wrong problem, sending you back to Diamond 1. This is healthy iteration, not failure. A practical tip: post the Double Diamond diagram in your project workspace and mark which phase you're currently in. It creates shared understanding and prevents premature convergence.
Good UI = intuitive at first glance — users never wonder what to click
Tip
Tip
Practice The Double Diamond Model in small, isolated examples before integrating into larger projects. Breaking concepts into small experiments builds genuine understanding faster than reading alone.
Practice Task
Note
Practice Task — (1) Write a working example of The Double Diamond Model from scratch without looking at notes. (2) Modify it to handle an edge case (empty input, null value, or error state). (3) Share your solution in the Priygop community for feedback.
Quick Quiz
Common Mistake
Warning
A common mistake with The Double Diamond Model is skipping edge case testing — empty inputs, null values, and unexpected data types. Always validate boundary conditions to write robust, production-ready ui ux code.
Key Takeaways
- The Double Diamond is a visual framework created by the UK Design Council in 2005 that maps the design process into four distinct phases: Discover, Define, Develop, and Deliver.
- Discover (Diverge): Open up the problem space. Research broadly — talk to users, analyze competitors, review analytics, explore adjacent industries. The goal is to learn as much as possible without filtering. Deliverables: research reports, interview transcripts, analytics summaries, empathy maps
- Define (Converge): Narrow down the findings into a clear, specific problem statement. Synthesize research through affinity mapping, identify patterns and themes, and define the core problem to solve. Deliverables: user personas, problem statements, 'How Might We' questions, prioritized opportunity areas
- Key insight: Most teams skip Diamond 1 entirely — they start with a solution ('build a chatbot') rather than a problem ('users can't find answers to common questions'). Diamond 1 ensures you're solving the right problem before you design anything